It is known that aquariums for containing fish are equipped with automatic food dispensers, also known as feeders, that allow the product to be distributed in the water usually at periodic and preset intervals.
These automatic dispensers mainly consist of a fixed or mobile container in which the food is placed, and are equipped with means for transferring the food into the water.
In order to distribute the food product, the dispensers are generally provided with means that allow the product to be discharged from the dispenser through the use of screw feeders or other conveyors that gradually push the product at periodic intervals, allowing it to descend by gravity.
The European patent EP05 14291 and the American U.S. Pat. No. 6082299 disclose a food dispenser for aquatic fauna which comprises a protective guard enclosing transfer means consisting of a worm screw housed in a channel of the guard starting from the food in feed area and ending in the dispensing area at the discharge outlet.
In other cases, the container is cylindrical in shape and positioned horizontally so that on rotation the upper opening in the cylinder is turned downwards; causing a predetermined quantity of product to be dispensed into the water.
These solutions, which are the most commonly used in this sector, present some drawbacks, the first of which is the difficulty in dispensing exact predetermined quantities of food, so that excessive amounts may be alternated with too little amounts.
This is due on one hand to the presence of the worm screw or screw feeder which during food transfer can cause the formation of lumps especially in the presence of humidity that block the flow of the food. Similarly, in the case of the cylindrical dispenser, the rotated food can also form lumps, causing irregular dispensing.
Furthermore, the screw feeder is generally positioned below a cylindrical vertical tank, dispensing the food by moving at right angles, that is picking up the food from above and transferring it horizontally towards the discharge outlet.
This represents another factor that has a negative effect on the homogeneous delivery of the food, since its accumulation in various overlying layers in the tank creates lumpy areas due to the weight and gravity compacting condition with downward pressure.
Another factor that has a negative effect on food delivery is humidity which, especially in the case of aquariums, penetrates the dispenser or even the food tank, leading even more to the formation of lumps of food, which notoriously represent the main obstacle in the correct dispensing of the food product.
The possibility of the humidity penetrating the dispenser and affecting the food is due to the fact that the devices are not equipped with closing elements at the product outlet, so that the food is constantly in contact with air saturated with humidity from the water below.
This causes all the imaginable consequences, including the formation of mould and of food lumps that block the outlets, sometimes even causing complete blockage of the dispenser.